1. Technical Field
The present invention relates to memory devices for use in electronic, such as microprocessor-based, systems, and more particularly to so-called “flash memory” devices for use in such systems.
2. Description of the Related Art
As is known in the art, many microprocessor-based devices and systems use so-called “flash memory” devices (i.e. a particular form of EEPROM (Electronically Erasable Programmable Read-Only Memory) to store data, software, etc. Such devices can include, for example, mobile telephones, electronic toys, cameras, and domestic appliances such as washing machines, etc. Indeed, almost every microprocessor-based product will typically use a flash memory.
However, a disadvantage to the use of flash memory is that a single bit error in the memory can often prevent a product or device from functioning. Indeed, one of the largest contributors to the probability of failure for a device incorporating a flash memory is the flash memory itself. As flash memory components are usually soldered to other components such as a main circuit board, a flash memory failure will often result in the need to replace not only the flash memory, but other components as well.
Single bit errors in flash memory can arise for a number of reasons, such as manufacturing defects or programming disturbances, as is known in the art. More recent advances in the technology used to implement flash memory, such as reductions in feature size and the practice of storing two bits in each cell, have tended to increase the rate of single bit errors in flash memory devices.
It is known to try to identify and compensate for bit errors occurring in flash memory devices, so as to try to avoid any such errors causing a “catastrophic” failure of the device. Such techniques typically use error correcting schemes and codes, but are often required to be implemented using bespoke or dedicated hardware, and/or can lead to undesirable delays in reading and/or writing data from and to the memory.
The Applicants believe therefore that there remains a need for an improved technique for increasing the reliability of memory devices and in particular of flash memory devices.